In an intense tale of psychological terror, a social worker discovers a force of evil greater than she imagined possible when she attempts to rescue a mysteriously silent young girl.

Devoted family services specialist Emily Jenkins (Renee Zellweger) has seen it all – lies, neglect, abuse – domestic horrors of every type. That is, until she takes on Case 39: the case of 10-year-old Lillith Sullivan (Jodelle Ferland), whose eerie, secretive family leaves Emily shaken and disturbed. When Lillith’s parents attempt to harm their only child in a late-night ritual, Emily intervenes. Heartbroken by Lillith’s loneliness and innocence, Emily decides to do something she has never allowed herself to do in the past: get personally involved. Hoping to do the right thing for the withdrawn girl, Emily offers Lillith a caring, happy home until she can find an adoptive family. That’s when the real terror begins.

What pushed Lillith’s family to the breaking point? Why does everyone who comes into contact with Lillith seem to suddenly become mad? And how will Emily survive the devastating secret fears that have come to the fore? To discover the truth, Emily must leave behind her rational beliefs and confront her most terrifying nightmares as she enters a supernatural realm where evil preys on humanity.